The University of Iowa Carver College of Medicine
What cardiovascular specialist Mark Anderson, M.D., Ph.D., and his colleagues are learning about an extremely rare disease that affects about 20 people worldwide could help lead to new treatments for millions of people with arrhythmias, or irregular heartbeats.
Most patients with Timothy syndrome don't live to see age 3. It is a rare genetic disorder that can cause an irregular heartbeat, a malformed heart, autism or other nervous system disorders. The disease is characterized by a heart condition that causes the heart muscle to take longer than usual to recharge between beats. This abnormality in the heart's electrical system can cause irregular heartbeats that can lead to sudden death.
In their research, Anderson, who is professor and director of the cardiovascular medicine division in the Department of Internal Medicine, and his colleagues showed that by blocking an enzyme called CaM kinase II, they were able to prevent irregular heartbeats in a heart cell model engineered to express the Timothy syndrome gene.
CaM kinase II was already known to play a role in arrhythmias, but Anderson's research helps uncover the enzyme's interplay with calcium channels that allow for calcium to enter heart cells. Calcium is necessary to trigger each heartbeat; in Timothy syndrome, a mutation causes the calcium channel to not work properly, leading to irregular heartbeats and the other complications.
The work by Anderson's team gives a better understanding of Timothy syndrome, but also points to CaM kinase II as a key player in heart muscle cell function -- suggesting that inhibiting this enzyme could be an effective way to treat, or prevent, arrhythmias and other types of heart conditions.